Environmental threats to fragile Antarctica

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When news that a giant iceberg broke free from the Larsen C ice shelf was confirmed on July 12, 2017, the global community was riveted by the environmental implications for the Antarctic and beyond. The mass of ice, at 5,800 square kilometers, is one of the largest icebergs ever recorded and left the Larsen C shelf reduced by about 12 percent. The A68 iceberg, born of a long-monitored rift, has broken into at least 11 smaller icebergs since and scientists are keeping a close watch on continued ice shelf activity.

East Antarctica accounts for two-thirds of the continent and is about the size of Australia, covered by an ice sheet so thick that it pushes the elevation height to 2.3 kilometers in what is a high polar desert. The Dome A mountain, peaking at more than 4 kilometers, is believed to be the coldest place on earth, in a place where sunlight disappears for six months of the year and winds sweep across the thick surface ice.

West Antarctica is lower, with the land submerged under the weight of ice across the millennia. The Antarctic Peninsula, where Larsen C extends along the Weddell Sea side, reaches far north enough to support lichens and moss at its tip and reach 1 or 2C temperatures in the summer months. A May 2017 study found that these mosses are more active, likely because of climate change, in the past 50 years.

The calving ice shelves aren’t the only changes occurring on Antarctica, as scientists and environmental advocacy groups work to understand how climate impacts the rich biodiversity and rare ecosystem.

For decades, most of the attention to Antarctica’s ice loss has focused on surface melt from warming surfaces on top of the ice, the warming ocean beneath them, and how the two interact. Scientists are now looking at how wind plays a role in the ice shelf loss. Antarctica is subject to föhn winds, which blast warm and very dry air downward, on the downwind side of mountain slopes, just as they do in the Alps or Scottish highlands. It wasn’t until 2010 that researchers first saw how significant an impact the winds have on the mountain range of the Antarctic Peninsula, even in the cold and dark of the winter months.

In 2010, the sun went down for the final time on June 13 as winter began. Yet one month later, a team of scientists monitoring instruments at Scar Inlet watched temperatures swing wildly from -34.4C to 10C in a “heat wave” that lasted for 36 hours. With the hot winds came snow melt and glacier ponding. New readings since then have reached 15.5C, with eight episodes recorded in September and October 2016.

In other cases, researchers observed blinding snows that weren’t actually falling. Beneath a blue sky, the föhn winds were driving existing snow – removing it from ice surfaces in a pattern similar to erosion. The winds helped to expose Larsen C in places where up to 60 meters of snow should have been, to just three. With the protective layer gone, the ice melts. Additionally, the winds push sea ice away from the ice shelves, removing what serves as the shelf support and creating conditions for further disintegration. The phenomenon is likely to increase on a warming planet and pose further challenges to Antarctica.

The finding is important but scientists continue to observe the effects of warming waters. On the Ross Sea sector of the Western Antarctic Ice Shelf (WAIS), a prolonged warming episode in 2016 lasted at least 15 days and was believed to be one of the top three such episodes ever recorded. The event, attributed at least in part to El Niño atmospheric and meteorological conditions, even triggered rainfall reported on two consecutive January days that appeared to accelerate the melting. It’s among many studies that have demonstrated warming conditions and melt patterns likely to affect sea level rise.

Warmer ocean waters beneath the ice serve “as kind of a blow torch on the underside of the ice shelf,” according to retired NASA climate scientist Robert Bindschadler, whose career at Antarctica included placing undersea buoys to record ocean temperature. Bindschadler told the New York Times in May 2017 that substantial loss of ice in just 10 years would not surprise him, and with the loss come dire projections for coastal cities and the 40 percent of humans who live within 100 kilometers of the sea.

Closer to Antarctica itself, those climate changes threaten plant and marine life. Emperor penguin, leopard seals, minke and blue whale, albatross and other sea birds are among those already seeing changes in their habitat, including the tiny krill fish that are critical to the food chain and ecosystem.

Another well-known threat to marine life in the Antarctic is plastic pollution. A total of 8 million metric tons currently ends up in the world’s oceans each year, and for a long time the threat to the Southern Ocean was overlooked because there are few manmade impacts there. About a dozen nations have research facilities there, with a population of no more than 5,000 scientists at any given time. Yet ocean currents transport plastic and microplastic particles at levels much higher than previously thought.

A June 2017 study from the British Antarctic Survey and University of Hull found levels of microplastics, found in everything from toothpaste to clothing fibers, at five times higher than what might be expected to come from just the scientists who live and study there. The Southern Ocean accounts for 5.4 percent of the world’s oceans, and researchers thought the Antarctic Circumpolar Current was nearly immune to transfer of plastics from other waters. They are reassessing what they know, and alarmed by the data.

“We have monitored the presence of large plastic items in Antarctica for over 30 years,” the team said. “While we know that bigger pieces of plastic can be ingested by seabirds or cause entanglements in seals, the effects of microplastics on marine animals in the Southern Ocean are as yet unknown.”

International legislation controlling the use and release of microplastics has not kept pace with the emerging environmental consequences of their production, they add. There is little said about this environmental concern in the Antarctic Treaty, and little data to support regulatory decision-making.

The Antarctic Treaty, administered from Argentina, is the primary legal document governing a land on which no one technically may claim sovereignty although several governments – including Argentina, Chile, the United States, Russia and the United Kingdom – have asserted or never withdrawn an interest.

The treaty dates back to 1959 and the Cold War. Manfred Reinke, a German scientist whose eight years as executive secretary of the Antarctic Treaty end in August 2017, said the “underlying aim is to enshrine Antarctica as a peaceful, demilitarized, nuclear-free region for all mankind offering freedom of scientific research and international cooperation.” At originally 12, there are now 53 nations party to the treaty.

Protection of Antarctica’s flora and fauna was initially added in 1964, with most changes since, including a Protocol on Environmental Protection enforced since 1998, focused on climate and the environment.

The international Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) was established in 1982 to protect Antarctic marine life, and is based in Australia. Its goal to protect krill, the small fish at the core of the Southern Ocean food ecosystem, has expanded to other fishing protections and regulations as well as the establishment of conservation areas. The largest such area in the world, covering 600,000 square miles in the Ross Sea, was designated a no-fishing zone by 24 nations and the European Union in October 2016. About a fourth is open for limited catch for scientific research use.